Overview
ISO 7380-2:2022 - Fasteners: Button head screws with reduced loadability - Part 2: Hexagon socket button head screws with collar - defines the dimensions, mechanical requirements and marking for steel hexagon socket button head screws with collar and reduced loadability. The standard covers metric coarse pitch threads M3 to M16, product grade A, and property classes 8.8 and 10.9 (marked with a leading zero when reduced loadability applies). It also explains how reduced loadability (caused by head geometry and socket penetration) limits the ultimate tensile load (head loadability assumed to be 80% of thread loadability).
Key topics and technical requirements
- Scope and material: Steel screws, metric coarse threads M3–M16, product grade A.
- Reduced loadability marking: Property class is preceded by a zero (e.g., 08.8, 010.9) to indicate limited ultimate tensile load.
- Minimum tensile loads: Table 4 gives the minimum ultimate tensile loads for reduced-load screws (for example, M8: 23 400 N for 08.8 and 30 500 N for 010.9). Values are derived as 80% of full-load figures in ISO 898-1.
- Dimensions and tolerances: Detailed head, socket and collar dimensions are in Table 1 and Table 2 (including socket depth t, socket width s/e, wall thickness w, head diameter and radii). Thread tolerancing follows ISO 965-1 (6g) and gauging guidance references ISO 23429.
- Thread length and testing: Reference thread lengths and minimum grip/shank dimensions are specified; partially and fully threaded length rules follow ISO 888 and ISO 4753 where applicable. For tensile testing of reduced-load screws, reference thread length requirements (e.g., b ≥ 3d for M16) are included.
- Surface condition and inspection: General requirements, coatings and surface discontinuities reference ISO 8992, ISO 4042, ISO 10683, ISO 6157-1 and acceptance inspection per ISO 3269.
- Marking and labelling: Product marking per ISO 898-1; package labelling must include reference to ISO 7380-2, thread size and length, property class, finish/coating, supplier ID, lot number and quantity.
Applications and who uses it
- Design and mechanical engineers specifying fasteners where head geometry (button head with collar) and predictable reduced load performance are critical.
- Fastener manufacturers and suppliers producing or certifying hexagon socket button head screws with collar to ensure dimensional conformity and correct property-class marking.
- Quality inspectors and procurement teams verifying tensile-load ratings, marking, packaging and traceability for assemblies in machinery, industrial equipment, electronics enclosures and general engineering applications where a low-profile button head is required but full head loadability is not assumed.
Related standards
Keywords: ISO 7380-2:2022, hexagon socket button head screws with collar, button head screws reduced loadability, M3 to M16, fasteners standard, property class 08.8 010.9, tensile load.